It looks a lot like Journey.
The game is exclusive to iOS and tvOS. Luckily I do use iOS and was planning to upgrade my phone soon anyway. And I do think that the minimalist philosophy behind thatgamecompany’s games is a good match for Apple’s similar focus on subtraction. That said, it would be preferable if other players are able to play this besides Apple users, especially as Sky is published by thatgamecompany itself (unlike Journey, which was published by Sony), so hopefully the exclusivity is only timed.